1. Technical Field
The present inventions relate to the components and the procedure for installing a trim assembly at a wall and ceiling junction, and, more particularly, relates to a self-adjusting trim assembly designed to hide unsightly gaps at the junction between the top of a stationary wall finish and a ceiling expected to move.
2. Description of the Related Art
As construction techniques improved in recent years, free span concrete ceilings (poured or pre-cast spans devoid of columns and beams for intermediate support) have come into common usage. These free span structures are usually supported by interior walls or beams at the core of the building and by walls or beams at the exterior of the building.
Exterior support structures are frequently subject to temperature variances and forces not present on and around the interior (core) support structures. The dynamics involved with the exterior support structures cause them to expand, contract and move at different rates than the core structures, resulting in an anticipated flex or movement of the ceiling being supported. Therefore, non-supporting walls constructed between support structures have to be able to withstand the expected movement of the ceilings above them without sustaining damage. To prevent damage to non-supporting walls, deflection allowances are designed into those walls which include deflection framing components and a deflection gap between the top of the stationary wall finishes and the ceiling expected to move.
Initial usage of free span ceilings was primarily in commercial buildings where drop ceilings hid the necessary deflection gaps between stationary elements of a non-supporting wall and a flexing ceiling above. Often in commercial spaces, the area above the drop ceiling was used to house the required electrical feeds, plumbing, fire protection piping and the HVAC ducting. Those areas above dropped ceilings often exceeded a foot in height. When this construction method began to be used in residential building, providing a dropped ceiling below the structural ceiling proved to be impractical. Electrical systems, plumbing, fire protection and HVAC were relocated into the walls or soffits and the dropped ceilings were eliminated. Therefore, the structural ceiling became the finished ceiling. This resulted in eliminating the extra height on each floor required above dropped ceilings. In a multistory building, omitting these extra heights and the dropped ceilings added up to become a significant savings. However, when the structural ceiling became the finished ceiling, the unsightly deflection gap at the top of all the non-supporting walls became visible.
It is commonly desirable to provide aesthetically pleasing junctions or intersections between walls and ceilings. When an unsightly deflection gap is visible due to anticipated flexing of the ceiling, making an aesthetically pleasing junction at the deflection gap between the stationary wall finishes and the ceiling requires a necessary treatment or covering for the exposed deflection gap.
In construction where it is not necessary to have a deflection gap, there are numerous methods of treating the junction between a stationary wall and a stationary ceiling, such as taping the joint (applying a paper or mesh tape angle and finishing compounds to the wall and ceiling junction to make an unbroken finish between the ceiling and the wall) or by applying a standard molding like a crown molding, a cove molding, a square stock molding, a beam, etc. to enhance the appearance of the wall and ceiling junction. However, there are few options for treating the junction between a stationary wall finish and a ceiling that is expected to flex as the ceiling's support members expand, contract or move due normal conditions expected to effect the support structures.
The current, common options for treating a deflecting gap between a stationary wall finish and a slightly deflecting ceiling are flat taping the top of the stationary wall finish (applying paper or mesh tape and finishing compound on the wall surface only with the edge of the tape as close to the ceiling as possible without touching the ceiling) and/or caulking the gap between the top of the stationary wall finish and the ceiling.
The chief advantage to flat taping (as illustrated in prior art FIG. 1) is that imperfections on the top edge of the wall finish materials and the fire or sound caulking is partially hidden by the tape. However, the flat taping option is labor intensive, has a built in crack at the top and generally results in an even more unsightly junction once the ceiling deflects down on the top of the tape, which crushes and permanently deforms the tape. (Once the ceiling migrates back upward, an unsightly gap is more pronounced.)
The caulking option is also somewhat unsightly because slight defects (uneven cuts, jagged edges, etc.) at the top of the wall finish material are visible, dust and dirt tend to accumulate in the caulk space over time and the caulk tends to distort when the ceiling migrates in an upward or downward direction. To minimize the unsightly appearance at the edges of the wall finish materials, a finishing bead (as illustrated in prior art FIG. 2) was often installed at the top of the wall finish material and finished with finishing compound prior to the installation of the caulk. If a finish bead is used to define the top edge of the wall finish material and hide defects, the caulk method is more costly for materials and more labor intensive than flat taping. Being that caulk tends to loose it's elasticity and bonding propensity over time, it eventually tends to allow small cracks and gaps to develop. In many fire resistant and sound deadening wall designs, caulk is a necessary component. Therefore the cost of the materials and labor for the caulk itself was not a factor in determining the best finishing application for the wall and ceiling junction.
Many trims that could hide an unsightly wall/ceiling gap have been designed through the years past. However, known trims were not self-adjusting and do not accommodate flex in the ceilings. Most known existing trim systems attached to the surfaces of the stationary wall and the stationary ceiling. Many known improvements incorporated concealed brackets and fasteners. While the trims for treating the junction between a stationary wall and a stationary ceiling were functional in their designed environment, they all had one thing in common. They were designed to be applied to the surface of a finished wall and a ceiling and they did not accommodate flexing of the ceiling without distortion or system failure.
One example of a trim system used in stationary wall and ceiling applications was taught in U.S. Pat. No. 4,555,885 by Ronald P. Raymond and William C. Andric (1985). This demonstrated an extruded, trim system where the trim has a barbed protrusion that was designed to friction fit in the gap between the wall and ceiling materials with a nearly flat element of the trim extending onto the ceiling and another nearly flat element of the trim extending onto the wall (having a basic right angle shape visible) which covers the gap between the wall finish and the ceiling finish. Wide variations in the joint width, caused by the flex of the ceiling, challenges the reliability of this system. This system also does not leave sufficient room for fire or sound caulks which are required in many fire and sound rated wall assemblies.
Another example of a trim system used in stationary wall and ceiling applications was taught in U.S. Pat. No. 4,461,135 by Dallas A. Anderson and Harlan J. Grayden (1984). This system is a 2 piece system of a plurality of slip-on clips and a trim piece that pushes onto the clips. This system functions in a manner similar to a slip-on J bead (a common edge treatment for drywall and other panel materials). This system attaches to the top of the finish panel for the wall system. This combination of clips and a trim piece is then manually adjusted after installation by sliding the trim into position immediately adjacent to the ceiling. Because this system is not self-adjusting, once the ceiling flexes in it's expected up and down migrations, a pronounced gap is developed. Being that this system is not self-adjusting, the trim would require periodic adjustment after installation.
A different approach to maintaining a pleasing appearance at the wall/ceiling junction was demonstrated in U.S. Pat. No. 6,581,353 by Ronald J. Augustine (2001), whereby the flexing of the ceiling is compensated through suspending the entire wall construction from the ceiling. This option creates a static wall/ceiling junction which can be finished using any existing finish or stationary trim system. The necessary gap that allows for flexing of the ceiling is just above the floor, with the deflection gap hidden by the baseboard. Lateral support for this wall construction system is at the bottom of the wall and is provided by using the sliding component of this invention. Drawbacks to this type of construction are the extremely high material, labor and fastener costs, the relative instability of the partitions at the base and the inability of this design to meet most fire and sound resistance ratings.
Numerous crown molding designs such as those shown in U.S. Pat. Nos. 5,426,901 by Jaroslav Indracek (1995), 5,433,048 by Jean P. Strasser (1995), 4,642,957 by Troy C. Edwards (1987) and 7,451,574 by Micheal Timothey Spek (2008) include many improvements in reducing costs of installation and material costs for use at the junction of a stationary wall and a stationary ceiling. While many of these designs incorporate improvements such as brackets and preformed corners to help hide fasteners and facilitate faster installations, the chief drawback to all these systems is that they were not designed for use at a junction between a stationary wall finish and a flexible ceiling.